I'm having trouble downloading PDFs and viewing PDFs embeded in banking institution pages in Firefox. When trying to download statements from Wells Fargo I get a setup.cgi file and when I try to view statements from Fifth Third Bank I get a Statement.jsp file. I have no trouble downloading these files while on a PC. I have Adobe Reader set as my default PDF reader and I also have the PDF for Firefox addon installed. Any ideas what's going on?
Try just renaming the extension and see if Preview is able to open it correctly. I've seen this behavior at times, and just putting the correct extension works.